The present invention relates to an electrocardiogram signal processing apparatus for automatically analyzing an electrocardiogram.
It is well known that a biological signal such as an electrocardiogram signal is analyzed by digital-processing. In such digital-processing, a analog source signal is converted into a digital signal, and smoothing and primary differential processes are performed by means of a digital filter for eliminating a noise and detecting a peak point, an onset point and an end point of a signal waveform. Consequently, characteristics of the signal waveform are extracted.
For instance, when an electrocardiogram is analyzed, a QRS complex of electrocardiogram waveforms is first detected, and on the basis of this result the respective onsets and ends of a P wave, a T wave and the QRS complex are determined, thereby measuring amplitudes and time intervals of respective waves. The thus measured values are employed as parameters for automatic analysis in relation to the electrocardiogram. Such electrocardiogram analyzes is performed by using digital filtering process which includes software.
Conduction abnormalities, especially the Wolff-Parkinson-White syndrome (hereafter called WPW syndrome) are known with respect to the electrocardiogram. The WPW syndrome electrocardiogram is characterized by having a short P-R interval (between the P onset and the Q onset), and a greater width of the QRS complex, in which a moderate slope known as the delta wave D is contained in the rising region of the R wave. In a conventional electrocardiogram analysis by using the primary differential process, it is quite difficult to accurately recognize the delta wave D, which causes low accuracy in the WPW syndrome detection.